/*
 Copyright 2006 Jerry Huxtable

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
package com.googlecode.blaisemath.graphics.swing;

/*
 * #%L
 * BlaiseGraphics
 * --
 * Copyright (C) 2009 - 2014 Elisha Peterson
 * --
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */

import java.awt.Font;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphVector;
import java.awt.geom.AffineTransform;
import java.awt.geom.FlatteningPathIterator;
import java.awt.geom.GeneralPath;
import java.awt.geom.PathIterator;
import java.awt.geom.Point2D;

/**
 * Stroke that renders text along a path.
 * 
 * @author Jerry Huxtable
 * @author Elisha Peterson
 */
class TextStroke implements Stroke {

    private String text;
    private Font font;
    private boolean stretchToFit = false;
    private boolean repeat = false;
    private final AffineTransform transform = new AffineTransform();
    private static final float FLATNESS = 1;

    public TextStroke(String text, Font font) {
        this(text, font, true, false);
    }

    public TextStroke(String text, Font font, boolean stretchToFit, boolean repeat) {
        this.text = text;
        this.font = font;
        this.stretchToFit = stretchToFit;
        this.repeat = repeat;
    }

    @Override
    public Shape createStrokedShape(Shape shape) {
        FontRenderContext frc = new FontRenderContext(null, true, true);
        GlyphVector glyphVector = font.createGlyphVector(frc, text);

        GeneralPath result = new GeneralPath();
        PathIterator it = new FlatteningPathIterator(shape.getPathIterator(null), FLATNESS);
        float[] points = new float[6];
        float moveX = 0, moveY = 0;
        float lastX = 0, lastY = 0;
        float thisX = 0, thisY = 0;
        int type = 0;
        float next = 0;
        int currentChar = 0;
        int length = glyphVector.getNumGlyphs();

        if (length == 0) {
            return result;
        }

        float factor = stretchToFit ? measurePathLength(shape) / (float) glyphVector.getLogicalBounds().getWidth() : 1.0f;
        float nextAdvance = 0;

        while (currentChar < length && !it.isDone()) {
            type = it.currentSegment(points);
            switch (type) {
                case PathIterator.SEG_MOVETO:
                    moveX = lastX = points[0];
                    moveY = lastY = points[1];
                    result.moveTo(moveX, moveY);
                    nextAdvance = glyphVector.getGlyphMetrics(currentChar).getAdvance() * 0.5f;
                    next = nextAdvance;
                    break;

                case PathIterator.SEG_CLOSE:
                    points[0] = moveX;
                    points[1] = moveY;
                // Fall into....

                case PathIterator.SEG_LINETO:
                    thisX = points[0];
                    thisY = points[1];
                    float dx = thisX - lastX;
                    float dy = thisY - lastY;
                    float distance = (float) Math.sqrt(dx * dx + dy * dy);
                    if (distance >= next) {
                        float r = 1.0f / distance;
                        float angle = (float) Math.atan2(dy, dx);
                        while (currentChar < length && distance >= next) {
                            Shape glyph = glyphVector.getGlyphOutline(currentChar);
                            Point2D p = glyphVector.getGlyphPosition(currentChar);
                            float px = (float) p.getX();
                            float py = (float) p.getY();
                            float x = lastX + next * dx * r;
                            float y = lastY + next * dy * r;
                            float advance = nextAdvance;
                            nextAdvance = currentChar < length - 1 ? glyphVector.getGlyphMetrics(currentChar + 1).getAdvance() * 0.5f : 0;
                            transform.setToTranslation(x, y);
                            transform.rotate(angle);
                            transform.translate(-px - advance, -py);
                            result.append(transform.createTransformedShape(glyph), false);
                            next += (advance + nextAdvance) * factor;
                            currentChar++;
                            if (repeat) {
                                currentChar %= length;
                            }
                        }
                    }
                    next -= distance;
                    lastX = thisX;
                    lastY = thisY;
                    break;
                    
                default:
                    // ignore
            }
            it.next();
        }

        return result;
    }

    public float measurePathLength(Shape shape) {
        PathIterator it = new FlatteningPathIterator(shape.getPathIterator(null), FLATNESS);
        float[] points = new float[6];
        float moveX = 0, moveY = 0;
        float lastX = 0, lastY = 0;
        float thisX = 0, thisY = 0;
        int type = 0;
        float total = 0;

        while (!it.isDone()) {
            type = it.currentSegment(points);
            switch (type) {
                case PathIterator.SEG_MOVETO:
                    moveX = lastX = points[0];
                    moveY = lastY = points[1];
                    break;

                case PathIterator.SEG_CLOSE:
                    points[0] = moveX;
                    points[1] = moveY;
                // Fall into....

                case PathIterator.SEG_LINETO:
                    thisX = points[0];
                    thisY = points[1];
                    float dx = thisX - lastX;
                    float dy = thisY - lastY;
                    total += (float) Math.sqrt(dx * dx + dy * dy);
                    lastX = thisX;
                    lastY = thisY;
                    break;
                    
                default:
                    // ignore
            }
            it.next();
        }

        return total;
    }
}
